The present invention relates to a silver halide photographic light-sensitive element containing a novel magenta-color-forming coupler.
After exposing a color silver halide photographic light-sensitive element to light, the element is typically developed with an aromatic primary amine developing agent. The developing agent is oxidized during development and reacts with a coupler to form a dye, with a color image thus being formed. In this system, a subtractive method is generally used for color reproduction, in which blue, green and red colors are reproduced by forming yellow, magenta and cyan color images which are in complementary relation thereto, respectively. In general, acylacetamide of dibenzoylmethane type couplers are employed for forming yellow color images; pyrazolone, cyanoacetyl, or indazolone type couplers are used for forming magenta color images; and phenol type couplers, for example, phenols and naphthols, are utilized for forming cyan color images.
To produce color photographs, couplers which form dyes are incorporated in a developer or in a light-sensitive photographic emulsion layer(s).
A variety of 5-pyrazolone type couplers for forming magenta color images are known. Known substituents at the 3-position of the 5-pyrazolone ring include alkyl groups, aryl groups, alkoxy groups, as described in U.S. Pat. No. 2,439,098, acylamino groups, as described in U.S. Pat. Nos. 2,369,489 and 2,600,788, ureido groups, as described in U.S. Pat. No. 3,558,319, and anilino groups. 3-Anilino-5-pyrazolone type couplers have often been described in the art since U.S. Pat. No. 2,311,081 (U.S. Pat. No. Re. 22,329) was issued and several improvements therein have been proposed. British Pat. No. 956,261 discloses that azomethine dyes obtained from derivatives in which the ortho position of the anilino group is substituted with an alkoxy group or a halogen atom have advantageous spectral absorption properties for color photography, in that undesired absorption in the red light region is particularly low.
Specific examples of diffusion resistant couplers of this type and are capable of being incorporated into photographic emulsions are described, for example, in U.S. Pat. Nos. 3,684,514, 3,930,861, 3,907,571, 3,928,044, 3,926,634 and 3,935,015, and Japanese Patent Application (OPI) No. 123033/74 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"). For example, the couplers described in U.S. Pat. No. 3,935,015 are 3-(acylaminoanilino)-5-pyrazolones represented by the formula (M) and are well known: ##STR3## wherein D.sub.1 represents an aryl group or a heterocyclic group, D.sub.2 represents a straight chain, branched chain or cyclic alkyl group having 7 to 23 carbon atoms, D.sub.3 represents a coupling-off group (defined hereinafter), and L represents a halogen atom or an alkoxy group having 1 to 18 carbon atoms.
These couplers have the characteristics that the undesired absorption of magenta azomethine dyes obtained upon color formation using the same in the red light region is low, the cut-off of the main absorption is good at the longer wavelength side, and magenta color images having a high color density are obtained because the coupling speed is high. Furthermore, the solubility in organic solvents having a high boiling point is improved, so that, after dissolving these couplers in organic solvents, the couplers can be emulsion-dispersed in an aqueous medium in the form of fine colloidal particles and then added to emulsions.
However, these couplers have the disadvantages that the degree of yellow staining at the unexposed portion after color development processing is high, and this degree of yellow staining increases upon light irradiation. They have the further disadvantages that color fading of the magenta color images obtained upon color development using these compounds occurs to a significant degree upon irradiation with light, and the color balance required for color photography is damaged by exposure to light, since, for example, in a color film or a color paper, particularly in a color paper, the color images are formed when three colors such as yellow, magenta and cyan combine with each other, but among these colors, the magenta color is not faster than any other color upon light irradiation. These disadvantages become fatal defects for color light-sensitive elements, such as color printing papers and the like. Thus, improved couplers which do not have these disadvantages have been strongly desired.